Sah windows. Draught Proofing. Sashwise

Draught-Proofing

Victorian Sash Windows are a functional and aesthetic design classic. They are one of the few window designs that open within their own confines, without the need to swing out or up. They are also a valuable and desirable feature of any period home. However, as many are now over 100 years old we almost take it for granted that they will be draughty and rattle, will let in excessive road noise, will be difficult to open and close, or won’t open and close at all. This really need not be the case as all of these issues can be resolved by our excellent and cost effective draught-proofing service.

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Routing out the top sash

Have Your Windows Always Been Like This?

When originally made many years ago your wooden sash windows would actually have functioned quite well. However over decades the wood can shrink, causing rattling and excessive draughts. Cords can break, and re-glazing with heavier modern glass can unbalance them. Built-up layers of old paint can seal up or obstruct smooth movement. It is these issues that our draught-proofing service resolves, and as it uses hard-wearing modern materials previously unavailable to the Victorian joiners your windows will now slide beautifully between hidden draught-proofing brushes, which will not only prevent draughts, but will also stop your windows rattling, and prevent them from resonating by audibly damping them, reducing road noise significantly. In a nutshell your windows will actually perform better than new.

Here is a brief overview of what is involved with our popular Draught-Proofing service. Move your mouse over the diagrams to see an animation.

Taking Apart The Window

To take apart the window we first remove the four inner staff beadings, this allows us to lift out the lower sliding sash.

The two vertical parting beads are then removed followed by the upper sliding sash. It is at this point that any jammed or painted shut sashes are released.

Cleaning The Sash Box

Now that the sashes have been removed we can uncover the sash pockets and remove the weights from the sash box. The voids within the sash box are vacuumed clearing them of any dust and rubble.

At this stage any apparent rot issues are repaired, the boxes are sanded down and cleaned. The outer ‘cheek’ of the sash box is waxed and the sash pulleys are lubricated to ensure smooth operation.

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Fitting the draught-proof strip to the top sash

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Fitting the draught-proof strip to the bottom sash

Balancing The Sashes

A correctly balanced sash window should open and close with ease and maintain its position whilst open, without wanting to slide shut. Original sliding sashes are not always correctly balanced, in most instances this is due to the sashes having been re-glazed at some point with modern glass, which is heavier.

To ensure that your window is correctly balanced we individually weigh the sashes and their corresponding sash weights. We can then adjust the sash weights; either by increasing their weight through adding coiled lead to the weights; or by replacing the original weights with lighter or heavier sash weights as appropriate. Once this process has been completed your sash windows will run smoothly.

Routing Out The Sashes For Draught-Proofing Carrier

An 8mm wide, 4mm deep groove, is routed out along the central length of the top rail of the upper sash. A discreet draught-proof carrier is placed within the groove so that it is flush with the timber. Hardwearing weatherproof brushes are slid into the carrier; these brushes provide a seal between the upper sash and the top of the sash box, eliminating any draughts when the window is closed.

This same process is repeated on the lower sash, with the groove being routed out along the back of the meeting rail. In both instances this draught-proofing system has been specially designed to be unobtrusive and to not detract from the traditional character of your sash windows

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Servicing a pulley and re-cording

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Fitting the draught-proof brush to a new staff bead.

Re-cording

The sash box is re-corded using a high quality waxed-cotton cord. The cord contains an interwoven polyester core that provides greater strength and durability, whilst the cotton exterior maintains the character of traditional sash cord. Once re-corded the weights are attached and re-inserted into the sash box.

Re-Fitting The Upper Sash

The upper sash is connected to the upper cords using phosphate-coated screws. The upper sash is then slide into place and tested to ensure smooth running.

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Fitting a new draught-proof parting bead (lower)

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Fixing a staff bead into place

Fitting New Draught-Proof Parting Beads

New timber parting beads that contain a concealed draught-proof carrier are measured, cut and inserted into the sides of the sash box in two sections. The top half section is fitted with the weatherproof brushes facing outwards, thereby pressing against the upper sash when it is in its closed position. The bottom half section of the parting bead is fitted with brushes facing inwards, so that brushes rest against the exterior sides of the lower sash when it is closed.

The specially designed characteristics of the new parting beads ensure that the sides of the sashes are sealed from possible drafts when the windows are closed. The brushes also provide the added benefits of reducing noise pollution; and ‘dampening’ the sashes so that they will no longer rattle in high winds, or resonate due to passing traffic.

Re-Fitting The Lower Sash

The lower sash is placed in position and the gap between where the upper and lower sash butt together is measured and an appropriate sized weatherproof brush is slid into the pile carrier of the lower sash. The sash is re-attached to the lower cords and tested to ensure smooth running.

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Finishing a staff bead with smooth white mastic

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A beautifully draught-proofed Sash Window

Fitting All New Staff Beads

New timber staff beads are measured, cut and fitted around all four internal sides of the sash box, thereby holding the lower sash in place. The new staffing beads have the same curved design as the original beadings but contain the discreet weatherproof brushes that provide the final phase of draught-proofing.

Finished!

A coat of micro porous exterior gloss paint is applied to the section of the parting bead that is exposed to the elements so that it is immediately weatherproof. Finally, a finish coat of white primer is applied to the new staffing beads and to any bare wood that may have been revealed during the initial cleaning up of the sash box.

The servicing and draught-proofing process is now complete. All those old annoyances of draughts and rattles have been removed and your sashes run smoothly with ease.